RFA: Get rid of tree annotation

[Michael Matz <matz at suse dot de>]

Hi,

When doing the whole expand-from-gimple thingy my ultimate goal was to get 
rid of the field tree_base.ann.  Unfortunately I wasn't completely ready 
for stage 3, and was left with CALL_EXPR which were still expanded as 
trees, which in turn use the common tree annotation for remembering the 
current statement in order to get profile information for builtin string 
expanders.

I have most of the patch to expand also calls from gimple statement ready 
since some time, but the patch is (a) huge and (b) touches very old expand 
code (and (c) would need a new target hook to satisfy me completely).  
(a) is not so much a problem as much of the size is attributable to 
s/tree/gimple/ type of changes, so might be accepable also for stage 3.  
But (b) is a problem.  While I have it working for our architectures I 
don't think it's that acceptable for stage 3.

But Richi still wanted to get rid of the common pointer in tree_base 
during stage 3, and I agree with him here.  Hence I added an intermediate 
solution, trading that pointer in all trees with a single global variable 
that stores the currently expanded gimple statement.

So, this patch reduces the size of all trees except 
PARM_DECL, VAR_DECL, RESULT_DECL by one pointer.  We still need the var 
annotation during into-ssa and outof-ssa.

I plan to submit the real patch, which then would get rid of the global 
variable (by rewriting builtins.c and calls.c to work on gimple 
statements) early during stage 1, once it opens.

While reviewing keep in mind that also ann->lp_nr is unused.  Since some 
time already it never is set to anything, hence all the code connected 
with it is dead.

Regstrapped on x86_64-linux (all langs+Ada), no regressions.  Okay for 
trunk?


Ciao,
Michael.
-- 
	* tree.h (union tree_ann_d): Don't declare.
	(tree_base): Remove ann field.
	(struct var_ann_d): Declare forward.
	(tree_result_decl, tree_parm_decl, tree_var_decl): Add ann field.
	(DECL_VAR_ANN_PTR): New macro.
	* tree-dfa.c (create_var_ann): Rewrite in terms of above macro,
	accept only VAR, PARM or RESULT decls.
	(create_tree_common_ann): Remove.
	(remove_referenced_var): Use DECL_VAR_ANN_PTR.
	* tree-eh.c (lookup_expr_eh_lp): Remove.
	* tree-flow-inline.h (var_ann, get_var_ann): Rewrite in terms of
	DECL_VAR_ANN_PTR.
	(ann_type, tree_common_ann, get_tree_common_ann): Remove.
	* tree-flow.h (enum tree_ann_type): Remove.
	(struct tree_ann_common_d): Remove.
	(struct var_ann_d): Remove common field.
	(union tree_ann_d): Remove.
	(tree_ann_t, tree_ann_common_t): Remove typedefs.
	(tree_common_ann, get_tree_common_ann, ann_type,
	create_tree_common_ann, lookup_expr_eh_lp): Don't declare.
	* tree-ssa.c (delete_tree_ssa): Use DECL_VAR_ANN_PTR.
	* tree.c (copy_node_stat): Use DECL_VAR_ANN_PTR.
	* builtins.c (expand_builtin_memcpy): Use
	currently_expanding_gimple_stmt instead of tree annotation.
	(expand_builtin_memset_args): Ditto.
	* cfgexpand.c (currently_expanding_gimple_stmt): Add global variable.
	(expand_call_stmt): Don't set tree annotation.
	(expand_gimple_basic_block): Set currently_expanding_gimple_stmt.
	* expr.c (expand_expr_real): Don't call lookup_expr_eh_lp.
	* gimple.h (currently_expanding_gimple_stmt): Declare.

Index: tree.h
===================================================================
--- tree.h.orig	2009-11-23 15:41:34.000000000 +0100
+++ tree.h	2009-11-23 15:53:41.000000000 +0100
@@ -356,7 +356,6 @@ enum omp_clause_code
 
    See the accessor macros, defined below, for documentation of the
    fields.  */
-union tree_ann_d;
 
 struct GTY(()) tree_base {
   ENUM_BITFIELD(tree_code) code : 16;
@@ -398,8 +397,6 @@ struct GTY(()) tree_base {
      in tree_base instead of tree_type is to save space.  The size of the
      field must be large enough to hold addr_space_t values.  */
   unsigned address_space : 8;
-
-  union tree_ann_d *ann;
 };
 
 struct GTY(()) tree_common {
@@ -2854,8 +2851,10 @@ struct GTY(()) tree_label_decl {
   int eh_landing_pad_nr;
 };
 
+struct var_ann_d;
 struct GTY(()) tree_result_decl {
   struct tree_decl_with_rtl common;
+  struct var_ann_d *ann;
 };
 
 struct GTY(()) tree_const_decl {
@@ -2873,6 +2872,7 @@ struct GTY(()) tree_const_decl {
 struct GTY(()) tree_parm_decl {
   struct tree_decl_with_rtl common;
   rtx incoming_rtl;
+  struct var_ann_d *ann;
 };
 
 
@@ -3082,8 +3082,15 @@ extern void decl_fini_priority_insert (t
 #define DECL_THREAD_LOCAL_P(NODE) \
   (VAR_DECL_CHECK (NODE)->decl_with_vis.tls_model >= TLS_MODEL_REAL)
 
+#define DECL_VAR_ANN_PTR(NODE) \
+  (TREE_CODE (NODE) == VAR_DECL ? &(NODE)->var_decl.ann \
+   : TREE_CODE (NODE) == PARM_DECL ? &(NODE)->parm_decl.ann \
+   : TREE_CODE (NODE) == RESULT_DECL ? &(NODE)->result_decl.ann \
+   : NULL)
+
 struct GTY(()) tree_var_decl {
   struct tree_decl_with_vis common;
+  struct var_ann_d *ann;
 };
 
 
Index: tree-dfa.c
===================================================================
--- tree-dfa.c.orig	2009-11-23 15:41:35.000000000 +0100
+++ tree-dfa.c	2009-11-23 15:53:41.000000000 +0100
@@ -133,12 +133,12 @@ create_var_ann (tree t)
   var_ann_t ann;
 
   gcc_assert (t);
-  gcc_assert (DECL_P (t));
-  gcc_assert (!t->base.ann || t->base.ann->common.type == VAR_ANN);
+  gcc_assert (TREE_CODE (t) == VAR_DECL
+	      || TREE_CODE (t) == PARM_DECL
+	      || TREE_CODE (t) == RESULT_DECL);
 
   ann = GGC_CNEW (struct var_ann_d);
-  ann->common.type = VAR_ANN;
-  t->base.ann = (tree_ann_t) ann;
+  *DECL_VAR_ANN_PTR (t) = ann;
 
   return ann;
 }
@@ -188,24 +188,6 @@ renumber_gimple_stmt_uids_in_blocks (bas
     }
 }
 
-/* Create a new annotation for a tree T.  */
-
-tree_ann_common_t
-create_tree_common_ann (tree t)
-{
-  tree_ann_common_t ann;
-
-  gcc_assert (t);
-  gcc_assert (!t->base.ann || t->base.ann->common.type == TREE_ANN_COMMON);
-
-  ann = GGC_CNEW (struct tree_ann_common_d);
-
-  ann->type = TREE_ANN_COMMON;
-  t->base.ann = (tree_ann_t) ann;
-
-  return ann;
-}
-
 /* Build a temporary.  Make sure and register it to be renamed.  */
 
 tree
@@ -654,7 +636,7 @@ remove_referenced_var (tree var)
       && (v_ann = var_ann (var)))
     {
       ggc_free (v_ann);
-      var->base.ann = NULL;
+      *DECL_VAR_ANN_PTR (var) = NULL;
     }
   gcc_assert (DECL_P (var));
   in.uid = uid;
Index: tree-eh.c
===================================================================
--- tree-eh.c.orig	2009-11-23 15:38:08.000000000 +0100
+++ tree-eh.c	2009-11-23 15:53:41.000000000 +0100
@@ -203,21 +203,6 @@ lookup_stmt_eh_lp (gimple t)
   return lookup_stmt_eh_lp_fn (cfun, t);
 }
 
-/* Likewise, but reference a tree expression instead.  */
-
-int
-lookup_expr_eh_lp (tree t)
-{
-  if (cfun && cfun->eh->throw_stmt_table && t && EXPR_P (t))
-    {
-      tree_ann_common_t ann = tree_common_ann (t);
-      if (ann)
-	return ann->lp_nr;
-    }
-  return 0;
-}
-
-
 /* First pass of EH node decomposition.  Build up a tree of GIMPLE_TRY_FINALLY
    nodes and LABEL_DECL nodes.  We will use this during the second phase to
    determine if a goto leaves the body of a TRY_FINALLY_EXPR node.  */
Index: tree-flow-inline.h
===================================================================
--- tree-flow-inline.h.orig	2009-11-23 15:38:08.000000000 +0100
+++ tree-flow-inline.h	2009-11-23 15:53:41.000000000 +0100
@@ -152,15 +152,8 @@ fill_referenced_var_vec (VEC (tree, heap
 static inline var_ann_t
 var_ann (const_tree t)
 {
-  var_ann_t ann;
-
-  if (!t->base.ann)
-    return NULL;
-  ann = (var_ann_t) t->base.ann;
-
-  gcc_assert (ann->common.type == VAR_ANN);
-
-  return ann;
+  const var_ann_t *p = DECL_VAR_ANN_PTR (t);
+  return p ? *p : NULL;
 }
 
 /* Return the variable annotation for T, which must be a _DECL node.
@@ -168,8 +161,9 @@ var_ann (const_tree t)
 static inline var_ann_t
 get_var_ann (tree var)
 {
-  var_ann_t ann = var_ann (var);
-  return (ann) ? ann : create_var_ann (var);
+  var_ann_t *p = DECL_VAR_ANN_PTR (var);
+  gcc_assert (p);
+  return *p ? *p : create_var_ann (var);
 }
 
 /* Get the number of the next statement uid to be allocated.  */
@@ -193,13 +187,6 @@ inc_gimple_stmt_max_uid (struct function
   return fn->last_stmt_uid++;
 }
 
-/* Return the annotation type for annotation ANN.  */
-static inline enum tree_ann_type
-ann_type (tree_ann_t ann)
-{
-  return ann->common.type;
-}
-
 /* Return the line number for EXPR, or return -1 if we have no line
    number information for it.  */
 static inline int
@@ -678,26 +665,6 @@ is_call_used (const_tree var)
 	      && pt_solution_includes (&cfun->gimple_df->callused, var)));
 }
 
-/* Return the common annotation for T.  Return NULL if the annotation
-   doesn't already exist.  */
-static inline tree_ann_common_t
-tree_common_ann (const_tree t)
-{
-  /* Watch out static variables with unshared annotations.  */
-  if (DECL_P (t) && TREE_CODE (t) == VAR_DECL)
-    return &var_ann (t)->common;
-  return &t->base.ann->common;
-}
-
-/* Return a common annotation for T.  Create the constant annotation if it
-   doesn't exist.  */
-static inline tree_ann_common_t
-get_tree_common_ann (tree t)
-{
-  tree_ann_common_t ann = tree_common_ann (t);
-  return (ann) ? ann : create_tree_common_ann (t);
-}
-
 /*  -----------------------------------------------------------------------  */
 
 /* The following set of routines are used to iterator over various type of
Index: tree-flow.h
===================================================================
--- tree-flow.h.orig	2009-11-23 15:38:08.000000000 +0100
+++ tree-flow.h	2009-11-23 15:53:41.000000000 +0100
@@ -125,24 +125,6 @@ struct GTY(()) ptr_info_def
 };
 
 
-/*---------------------------------------------------------------------------
-		   Tree annotations stored in tree_base.ann
----------------------------------------------------------------------------*/
-enum tree_ann_type { TREE_ANN_COMMON, VAR_ANN };
-
-struct GTY(()) tree_ann_common_d {
-  /* Annotation type.  */
-  enum tree_ann_type type;
-
-  /* Record EH landing pad number into a statement tree created
-     during RTL expansion (see gimple_to_tree).  */
-  int lp_nr;
-
-  /* Pointer to original GIMPLE statement.  Used during RTL expansion
-     (see gimple_to_tree).  */
-  gimple stmt;
-};
-
 /* It is advantageous to avoid things like life analysis for variables which
    do not need PHI nodes.  This enum describes whether or not a particular
    variable may need a PHI node.  */
@@ -192,8 +174,6 @@ enum noalias_state {
 
 
 struct GTY(()) var_ann_d {
-  struct tree_ann_common_d common;
-
   /* Used when building base variable structures in a var_map.  */
   unsigned base_var_processed : 1;
 
@@ -318,20 +298,10 @@ typedef struct immediate_use_iterator_d
 
 
 
-union GTY((desc ("ann_type ((tree_ann_t)&%h)"))) tree_ann_d {
-  struct tree_ann_common_d GTY((tag ("TREE_ANN_COMMON"))) common;
-  struct var_ann_d GTY((tag ("VAR_ANN"))) vdecl;
-};
-
-typedef union tree_ann_d *tree_ann_t;
 typedef struct var_ann_d *var_ann_t;
-typedef struct tree_ann_common_d *tree_ann_common_t;
 
-static inline tree_ann_common_t tree_common_ann (const_tree);
-static inline tree_ann_common_t get_tree_common_ann (tree);
 static inline var_ann_t var_ann (const_tree);
 static inline var_ann_t get_var_ann (tree);
-static inline enum tree_ann_type ann_type (tree_ann_t);
 static inline void update_stmt (gimple);
 static inline int get_lineno (const_gimple);
 
@@ -556,7 +526,6 @@ extern const char *op_symbol_code (enum
 extern var_ann_t create_var_ann (tree);
 extern void renumber_gimple_stmt_uids (void);
 extern void renumber_gimple_stmt_uids_in_blocks (basic_block *, int);
-extern tree_ann_common_t create_tree_common_ann (tree);
 extern void dump_dfa_stats (FILE *);
 extern void debug_dfa_stats (void);
 extern void debug_referenced_vars (void);
@@ -856,7 +825,6 @@ extern void add_stmt_to_eh_lp (gimple, i
 extern bool remove_stmt_from_eh_lp (gimple);
 extern bool remove_stmt_from_eh_lp_fn (struct function *, gimple);
 extern int lookup_stmt_eh_lp_fn (struct function *, gimple);
-extern int lookup_expr_eh_lp (tree);
 extern int lookup_stmt_eh_lp (gimple);
 extern bool maybe_clean_eh_stmt_fn (struct function *, gimple);
 extern bool maybe_clean_eh_stmt (gimple);
Index: tree-ssa.c
===================================================================
--- tree-ssa.c.orig	2009-11-23 15:41:35.000000000 +0100
+++ tree-ssa.c	2009-11-23 15:53:41.000000000 +0100
@@ -1138,9 +1138,11 @@ delete_tree_ssa (void)
     {
       if (is_global_var (var))
 	continue;
-      if (var->base.ann)
-        ggc_free (var->base.ann);
-      var->base.ann = NULL;
+      if (var_ann (var))
+	{
+	  ggc_free (var_ann (var));
+	  *DECL_VAR_ANN_PTR (var) = NULL;
+	}
     }
   htab_delete (gimple_referenced_vars (cfun));
   cfun->gimple_df->referenced_vars = NULL;
Index: tree.c
===================================================================
--- tree.c.orig	2009-11-23 15:41:34.000000000 +0100
+++ tree.c	2009-11-23 15:53:41.000000000 +0100
@@ -955,7 +955,8 @@ copy_node_stat (tree node MEM_STAT_DECL)
   TREE_CHAIN (t) = 0;
   TREE_ASM_WRITTEN (t) = 0;
   TREE_VISITED (t) = 0;
-  t->base.ann = 0;
+  if (code == VAR_DECL || code == PARM_DECL || code == RESULT_DECL)
+    *DECL_VAR_ANN_PTR (t) = 0;
 
   if (TREE_CODE_CLASS (code) == tcc_declaration)
     {
Index: builtins.c
===================================================================
--- builtins.c.orig	2009-11-23 15:41:34.000000000 +0100
+++ builtins.c	2009-11-23 16:03:43.000000000 +0100
@@ -3259,7 +3259,6 @@ expand_builtin_memcpy (tree exp, rtx tar
       rtx dest_mem, src_mem, dest_addr, len_rtx;
       HOST_WIDE_INT expected_size = -1;
       unsigned int expected_align = 0;
-      tree_ann_common_t ann;
 
       /* If DEST is not a pointer type, call the normal function.  */
       if (dest_align == 0)
@@ -3270,9 +3269,9 @@ expand_builtin_memcpy (tree exp, rtx tar
       if (src_align == 0)
 	return NULL_RTX;
  
-      ann = tree_common_ann (exp);
-      if (ann)
-        stringop_block_profile (ann->stmt, &expected_align, &expected_size);
+      if (currently_expanding_gimple_stmt)
+        stringop_block_profile (currently_expanding_gimple_stmt,
+				&expected_align, &expected_size);
 
       if (expected_align < dest_align)
 	expected_align = dest_align;
@@ -3737,7 +3736,6 @@ expand_builtin_memset_args (tree dest, t
   rtx dest_mem, dest_addr, len_rtx;
   HOST_WIDE_INT expected_size = -1;
   unsigned int expected_align = 0;
-  tree_ann_common_t ann;
 
   dest_align = get_pointer_alignment (dest, BIGGEST_ALIGNMENT);
 
@@ -3745,9 +3743,9 @@ expand_builtin_memset_args (tree dest, t
   if (dest_align == 0)
     return NULL_RTX;
 
-  ann = tree_common_ann (orig_exp);
-  if (ann)
-    stringop_block_profile (ann->stmt, &expected_align, &expected_size);
+  if (currently_expanding_gimple_stmt)
+    stringop_block_profile (currently_expanding_gimple_stmt,
+			    &expected_align, &expected_size);
 
   if (expected_align < dest_align)
     expected_align = dest_align;
Index: cfgexpand.c
===================================================================
--- cfgexpand.c.orig	2009-11-23 15:41:35.000000000 +0100
+++ cfgexpand.c	2009-11-23 16:25:22.000000000 +0100
@@ -49,6 +49,10 @@ along with GCC; see the file COPYING3.
    into RTL.  */
 struct ssaexpand SA;
 
+/* This variable holds the currently expanded gimple statement for purposes
+   of comminucating the profile info to the builtin expanders.  */
+gimple currently_expanding_gimple_stmt;
+
 /* Return an expression tree corresponding to the RHS of GIMPLE
    statement STMT.  */
 
@@ -1756,7 +1760,6 @@ expand_call_stmt (gimple stmt)
 {
   tree exp;
   tree lhs = gimple_call_lhs (stmt);
-  tree fndecl = gimple_call_fndecl (stmt);
   size_t i;
 
   exp = build_vl_exp (CALL_EXPR, gimple_call_num_args (stmt) + 3);
@@ -1782,15 +1785,6 @@ expand_call_stmt (gimple stmt)
   SET_EXPR_LOCATION (exp, gimple_location (stmt));
   TREE_BLOCK (exp) = gimple_block (stmt);
 
-  /* Record the original call statement, as it may be used
-     to retrieve profile information during expansion.  */
-
-  if (fndecl && DECL_BUILT_IN (fndecl))
-    {
-      tree_ann_common_t ann = get_tree_common_ann (exp);
-      ann->stmt = stmt;
-    }
-
   if (lhs)
     expand_assignment (lhs, exp, false);
   else
@@ -3106,6 +3100,7 @@ expand_gimple_basic_block (basic_block b
       basic_block new_bb;
 
       stmt = gsi_stmt (gsi);
+      currently_expanding_gimple_stmt = stmt;
 
       /* Expand this statement, then evaluate the resulting RTL and
 	 fixup the CFG accordingly.  */
@@ -3203,6 +3198,8 @@ expand_gimple_basic_block (basic_block b
 	}
     }
 
+  currently_expanding_gimple_stmt = NULL;
+
   /* Expand implicit goto and convert goto_locus.  */
   FOR_EACH_EDGE (e, ei, bb->succs)
     {
Index: expr.c
===================================================================
--- expr.c.orig	2009-11-23 15:38:08.000000000 +0100
+++ expr.c	2009-11-23 16:06:55.000000000 +0100
@@ -7157,8 +7157,7 @@ rtx
 expand_expr_real (tree exp, rtx target, enum machine_mode tmode,
 		  enum expand_modifier modifier, rtx *alt_rtl)
 {
-  int lp_nr = 0;
-  rtx ret, last = NULL;
+  rtx ret;
 
   /* Handle ERROR_MARK before anybody tries to access its type.  */
   if (TREE_CODE (exp) == ERROR_MARK
@@ -7168,13 +7167,6 @@ expand_expr_real (tree exp, rtx target,
       return ret ? ret : const0_rtx;
     }
 
-  if (flag_non_call_exceptions)
-    {
-      lp_nr = lookup_expr_eh_lp (exp);
-      if (lp_nr)
-	last = get_last_insn ();
-    }
-
   /* If this is an expression of some kind and it has an associated line
      number, then emit the line number before expanding the expression.
 
@@ -7201,25 +7193,6 @@ expand_expr_real (tree exp, rtx target,
       ret = expand_expr_real_1 (exp, target, tmode, modifier, alt_rtl);
     }
 
-  /* If using non-call exceptions, mark all insns that may trap.
-     expand_call() will mark CALL_INSNs before we get to this code,
-     but it doesn't handle libcalls, and these may trap.  */
-  if (lp_nr)
-    {
-      rtx insn;
-      for (insn = next_real_insn (last); insn;
-	   insn = next_real_insn (insn))
-	{
-	  if (! find_reg_note (insn, REG_EH_REGION, NULL_RTX)
-	      /* If we want exceptions for non-call insns, any
-		 may_trap_p instruction may throw.  */
-	      && GET_CODE (PATTERN (insn)) != CLOBBER
-	      && GET_CODE (PATTERN (insn)) != USE
-	      && insn_could_throw_p (insn))
-	    make_reg_eh_region_note (insn, 0, lp_nr);
-	}
-    }
-
   return ret;
 }
 
Index: gimple.h
===================================================================
--- gimple.h.orig	2009-11-23 15:41:35.000000000 +0100
+++ gimple.h	2009-11-23 16:02:24.000000000 +0100
@@ -769,6 +769,10 @@ extern size_t const gimple_ops_offset_[]
 /* Map GIMPLE codes to GSS codes.  */
 extern enum gimple_statement_structure_enum const gss_for_code_[];
 
+/* This variable holds the currently expanded gimple statement for purposes
+   of comminucating the profile info to the builtin expanders.  */
+extern gimple currently_expanding_gimple_stmt;
+
 gimple gimple_build_return (tree);
 
 gimple gimple_build_assign_stat (tree, tree MEM_STAT_DECL);